1. Field of the Invention
The present invention relates to a conversion method employed to convert sequentially information blocks, each of which is extracted sequentially from information sequence and acts as a conversion unit, into code blocks. More particularly, the present invention relates to a conversion method and a conversion device which are capable of converting the information blocks into the code blocks through simple procedures, while taking account of suppression of a direct current component.
The present invention also relates to a restoration method and a restoration device which are optimal to restore the code blocks, which are converted by using the above conversion method, to original information blocks.
2. Description of the Prior Art
In the prior art, in order to remove defects such as restoration error caused due to baseline shift, etc. when information blocks each of which is extracted sequentially from information sequence and acts as a conversion unit are converted sequentially into code blocks, various conversion methods have been known which intend to realize the conversion taking account of suppression of a direct current component.
For example, in Patent Application Publication (KOKAI) Sho 59-200562, a conversion method has been disclosed which intends to realize the conversion while taking suppression of the direct current component into consideration. According to this conversion method, when 8-bit information blocks are converted into 10 bit code blocks, codes in which xe2x80x9c1xe2x80x9d and xe2x80x9c0xe2x80x9d are equal or close in number to each other are selected as a code conversion candidate from codes of 210=1024 patterns, and then the selected code conversion candidates are allocated to the codes of 28=256 patterns so as to correlate the code conversion candidates with the codes respectively.
Also, for example, in Patent Application Publication (KOKAI) Sho 60-107921, another conversion method has been disclosed which intends to realize the conversion while considering suppression of the direct current component. According to this conversion method, codes with the small bit number are converted into codes with the large bit number, then codes which do not contain the direct current component and which have patterns whose change points of information level are separated by more than two bits, codes which have patterns in which change points of information level are separated by more than two bits but the net positive or negative direct current component is suppressed within the previously determined range, or the like are selected as the code conversion candidate from the latter codes with the large bit number, and then a plurality of selected code conversion candidates are allocated to the codes with the small bit number so as to correlate the code conversion candidates with the codes respectively.
However, such a problem to be solved exists in the above conversion methods in the prior art that procedures required for converting the information blocks into the code blocks while taking account of suppression of the direct current component become complicated.
In other words, according to the conversion method disclosed in Patent Application Publication (KOKAI) Sho 59-200562, because only 193 codes in which xe2x80x9c1xe2x80x9d and xe2x80x9c0xe2x80x9d are contained equally in number are present in the codes of 210=1024 patterns, 63 patterns of the codes in which xe2x80x9c1xe2x80x9d and xe2x80x9c0xe2x80x9d are close in number must also be selected as the code conversion candidate. In this case, further the procedure of compensating difference between xe2x80x9c1xe2x80x9d and xe2x80x9c0xe2x80x9d is requested.
As a result, the procedures required to convert the information blocks into the code blocks with considering the suppression of the direct current component become complicated.
In contrast, according to the conversion method disclosed in Patent Application Publication (KOKAI) Sho 60-107921, patterns in which the change points of information level are separated by more than two bits but the net positive or negative direct current component is suppressed within the previously determined range are selected as the code conversion candidate. In this case, the procedure of eliminating the net positive or negative direct current component is further requested. As a result, the procedures required to convert the information blocks into the code blocks with considering the suppression of the direct current component become complicated.
Therefore, interested persons earnestly look forward to development of a new technology which are capable of converting the information blocks into the code blocks through simple procedures while taking account of suppression of the direct current component.
The present invention has been made in light of the above circumstances and it is an object of the present invention to provide a conversion method and a conversion device which are capable of converting information blocks into code blocks through simple procedures, while taking account of suppression of a direct current component, by dividing information blocks, each of which is extracted sequentially from information sequence and acts as a conversion unit, into a plurality of original subblocks, then generating inverted subblocks containing inverted information, which are obtained by inverting all original information allocated to one or more segments contained in divided original subblocks, while correlating the original subblocks with the inverted subblocks respectively, and then combining together a plurality of original subblocks and a plurality of generated inverted subblocks.
It is another object of the present invention to provide a restoration method and a restoration device which are optimal to restore the code blocks, which are converted by using the above conversion method, to original information blocks.
In order to achieve the above object, there is provided a conversion method of converting sequentially information blocks, each of which is extracted sequentially from an information sequence and acts as a conversion unit, into code blocks, the method comprising the steps of: dividing the information blocks into a plurality of original subblocks; generating a plurality of inverted subblocks containing inverted information, which are obtained by inverting all original information being allocated to one or more segments contained in original subblocks, while correlating the original subblocks with the inverted subblocks respectively; and converting the information blocks into the code blocks by combining the plurality of original subblocks and the plurality of generated inverted subblocks together.
According to the present invention, the information blocks are converted into the code blocks by dividing the information blocks which are extracted sequentially from an information sequence and acts as a conversion unit into a plurality of original subblocks, generating a plurality of inverted subblocks containing inverted information, which are obtained by inverting all original information being allocated to one or more segments contained in original subblocks, while correlating the original subblocks with the inverted subblocks respectively, and converting the information blocks into the code blocks by combining the plurality of original subblocks and the plurality of generated inverted subblocks together. Therefore, the information blocks each serving as a conversion unit are converted into the code blocks in which the original information allocated to every segment contained in the information blocks and the inverted information are combined together such that the numbers of the original information in a block acting as a conversion unit and the inverted information are balanced. As a result, the information blocks can be converted into the code blocks via simple procedures while suppressing the direct current component.
In the preferred embodiment of the present invention, each of the inverted subblocks is inserted between any original subblocks of the plurality of original subblocks when the plurality of original subblocks and the plurality of inverted subblocks are combined together.
In the preferred embodiment of the present invention, each of the inverted subblocks is inserted adjacent to the corresponding original subblock of the plurality of original subblocks when the plurality of original subblocks and the plurality of inverted subblocks are combined together.
In order to achieve the above object, there is provided a restoration method of restoring code blocks into original information blocks, the code blocks being converted from information blocks by dividing the information blocks each of which is extracted sequentially from the information sequence and acts as a conversion unit into a plurality of original subblocks, then generating a plurality of inverted subblocks containing inverted information which are obtained by inverting all original information being allocated to one or more segments contained in the original subblocks respectively while correlating the original subblocks with the inverted subblocks, and then combining the plurality of original subblocks and the plurality of generated inverted subblocks together, the method comprising the step of: restoring the code blocks derived by conversion to the original information blocks by sampling the original information, which are allocated to one or more segments contained in the original subblocks respectively, from respective original subblocks of the code blocks obtained by the conversion.
According to the present invention, the code blocks derived by conversion are restored to the original information blocks by sampling the original information, which are allocated to one or more segments contained in the original subblocks respectively, from respective original subblocks of the code blocks obtained by the conversion. Therefore, the restoration method which is optimal to restore the code blocks converted by using the above conversion method to the original information blocks can be achieved.
In the preferred embodiment of the present invention, the restoration method further comprises the steps of: sampling the inverted information, which are allocated to one or more segments contained in the inverted subblocks respectively, from respective inverted subblocks of the code blocks; executing coincidence decision to decide whether or not at least one combination in which both information coincide with each other is present in a plurality of combinations of the sampled original information and the sampled inverted information corresponding to the sampled original information; and deeming that an abnormal condition is caused when it is decided according to result of the coincidence decision that at least one combination in which both information coincide with each other is present.
According to this embodiment, when it is decided according to result of the coincidence decision that at least one combination in which both information coincide with each other is present, generation of the abnormal condition is deemed by sampling the inverted information, which are allocated to one or more segments contained in the inverted subblocks respectively, from respective inverted subblocks of the code blocks, and executing coincidence decision to decide whether or not at least one combination in which both information coincide with each other is present in a plurality of combinations of the sampled original information and the sampled inverted information corresponding to the sampled original information. Therefore, for example, if a request for providing the effect as to the generation of any abnormal condition from the sender to the destination is generated when the code blocks converted by the first conversion device are transmitted via the transmission line, the sender can inform the destination of the generation of the abnormal condition without fail by including forcibly at least one combination, in which the original information and the corresponding inverted information coincide with each other, into the code blocks on the sender side.
In the preferred embodiment of the present invention, the abnormal state contains transmission error and restoration error.
According to this embodiment, the abnormal state contains transmission error and restoration error. In this case, as the result that generation of the code error such as the transmission error, the restoration error, etc. is assumed when the combinations in which the original information and the corresponding inverted information coincide with each other are present, the restoring device which makes it possible to detect the code error easily can be achieved.
Also, in order to achieve the above object, there is provided a conversion device for converting sequentially information blocks, each of which is extracted sequentially from an information sequence and acts as a conversion unit, into code blocks, the device comprising: a dividing means for dividing the information blocks into a plurality of original subblocks; a generating means for generating a plurality of inverted subblocks containing inverted information, which are obtained by inverting all original information being allocated to one or more segments contained in original subblocks, while correlating the original subblocks with the inverted subblocks respectively; and a combining means combining the plurality of original subblocks and the plurality of generated inverted subblocks together to convert the information blocks into the code blocks.
According to this embodiment, first the dividing means divides the information blocks into a plurality of original subblocks. Then, the generating means generates a plurality of inverted subblocks containing inverted information, which are obtained by inverting all original information being allocated to one or more segments contained in original subblocks, while correlating the original subblocks with the inverted subblocks respectively. Then, the combining means combines the plurality of original subblocks and the plurality of generated inverted subblocks together to convert the information blocks into the code blocks.
In this manner, according to this embodiment, the information blocks each serving as a conversion unit are converted into the code blocks in which the original information allocated to every segment contained in the information blocks and the inverted information are combined together, and thus the original information in a block acting as a conversion unit and the inverted information are balanced in number. As a result, while taking suppression of the direct current component into consideration, the information blocks can be converted into the code blocks through simple procedures.
In the preferred embodiment of the present invention, the combining means inserts each of the inverted subblocks between any original subblocks of the plurality of original subblocks when combining the plurality of original subblocks and the plurality of inverted subblocks together.
In the preferred embodiment of the present invention, the combining means inserts each of the inverted subblocks adjacent to the corresponding original subblock of the plurality of original subblocks when combining the plurality of original subblocks and the plurality of inverted subblocks together.
Also, in order to achieve the above object, there is provided a restoration device for restoring code blocks into original information blocks, the code blocks being converted from information blocks by dividing the information blocks each of which is extracted sequentially from the information sequence and acts as a conversion unit into a plurality of original subblocks, then generating a plurality of inverted subblocks containing inverted information which are obtained by inverting all original information being allocated to one or more segments contained in the original subblocks respectively while correlating the original subblocks with the inverted subblocks, and then combining the plurality of original subblocks and the plurality of generated inverted subblocks together, the device comprising: an original information sampling means for sampling the original information, which are allocated to one or more segments contained in the original subblocks respectively, from respective original subblocks of the code blocks obtained by the conversion.
According to this embodiment, the original information sampling means restores the code blocks each serving as the restoration unit to the original information blocks by sampling the original information, which are allocated to one or more segments contained in the original subblocks respectively, from respective original subblocks of the code blocks obtained by the conversion. Therefore, the restoration device which is optimal to restore the code blocks converted by using the above conversion method to the original information blocks can be achieved.
In the preferred embodiment of the present invention, the restoration device further comprises: an inverted information sampling means for sampling the inverted information, which are allocated to one or more segments contained in the inverted subblocks respectively, from respective inverted subblocks of the code blocks; and a coincidence deciding means for executing coincidence decision to decide whether or not at least one combination in which both information coincide with each other is present in a plurality of combinations of the original information sampled by the original information sampling means and the inverted information sampled by the inverted information sampling means corresponding to the original information; wherein generation of an abnormal condition is deemed when it is decided according to result of the coincidence decision made by the coincidence deciding means that at least one combination in which both information coincide with each other is present.
According to this embodiment, the inverted information sampling means samples the inverted information, which are allocated to one or more segments contained in the inverted subblocks respectively, from respective inverted subblocks of the code blocks. Then, the coincidence deciding means executes coincidence decision to decide whether or not at least one combination in which both information coincide with each other is present in a plurality of combinations of the original information sampled by the original information sampling means and the inverted information sampled by the inverted information sampling means corresponding to the original information. Thus, generation of an abnormal condition is deemed when it is decided according to result of the coincidence decision made by the coincidence deciding means that at least one combination in which both information coincide with each other is present. Therefore, for example, if a request for providing the effect as to the generation of any abnormal condition from the sender to the destination is generated when the code blocks converted by the first conversion device are transmitted via the transmission line, the sender can inform the destination of the generation of the abnormal condition without fail by including forcibly at least one combination, in which the original information and the corresponding inverted information coincide with each other, into the code blocks on the sender side.
In the preferred embodiment of the present invention, the abnormal state contains transmission error and restoration error.
According to this embodiment, the abnormal state contains transmission error and restoration error. In this case, as the result that generation of the code error such as the transmission error, the restoration error, etc. is assumed when at least one combination in which the original information and the corresponding inverted information coincide with each other is present, the restoring device which makes it possible to detect the code error easily can be achieved.
The nature, principle and utility of the invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings.